Anemones
were at one time thought to be plants, even the name of the class to
which they belong, Anthozoa, means
"flowerlike." However, they are animals, all able and
carnivorous predators, and certainly not in need of the marine
equivalent of the "birds and the bees" to carry on new
generations. Anemones have developed a remarkably large variety of
methods to reproduce in their natural environment.

Sexes of most species are separate with fertilization taking place in
open water simply by the animals releasing their sperm and eggs. Sexual
reproduction by external means is usually prompted by the phases of the
moon with mass spawnings occurring at night during the first phase of a
new moon. This ensures the full opportunity for eggs and sperm to unite
and for the microscopic medusa-like larvae produced to join the
zooplankton, all under the cover of darkness and safe from predators.
They are then swept by the currents to settle and establish elsewhere.

Some anemones produce tiny complete replicas of themselves within
their body cavities as a result of internal fertilization and are spewed
out when fully developed. To ensure the maximum success of this
particular method, these anemones are hermaphroditic, having both male
and female reproductive systems.

Others increase their numbers asexually by division of the parent or
smaller versions of the parent are sometimes produced as buds or
offsets.

Although not all anemones will reproduce in captivity some, like a
small number of species belonging to the rock anemones family
Aiptasiidae, have earned the reputation of becoming pests in the
aquarium by rapidly reaching plague proportions. They usually appear
after hitching a ride on live rock and can take over an aquarium if not
controlled.•••